aight guys, i'm havin some trouble with my turbo sohc. i blew a head gasket a few weeks ago and replaced it. i lined everything up and set the cam timing perfectly. i drove it around for a couple weeks and noticed crappy gas milage, which would probably mean my cam timing is off. i checked the ignition timing and set the base timing to 11degrees, which was the dizzy all the way advanced. anyways, i had brian fisher at rev-tech motorsports in woodbridge, va look at it and try at least give me a base map for my hondata that would maintain some gas milage. we removed the cam gear cover and set it to tdc and, sure enough, it was perfectly on. whenever we made a pass on the dyno, the timing light would stop flashing when the rpm's went passed about 3k rpm.
i have a stock head gasket, stock cam gear, and rc750's with an s200. anyone ever had this prob before with a sohc motor?

what else should i check besides the cam timing if this is happening?

btw, half way through the dyno session we replaced the dizzy with another one and had the same problem. any input would be greatly appreciated, thanks!!!!

 

are you positive that your ignition timing is dead on? Did you use the jumper cable when you timed it?

 

alot of sohc's have problems with the base timing after swaping to a obdI ecu. so with the dizzy all the way advanced it will only go upto 11 correct. there are a couple things you can do here.

1: notch the dizzy a little bit to allow it to advance. base time for a y8 is 12 so your not far off.

2: advance your came gear by 1 mark which would be 2 degree's, and you should be able to get it to 12 then.

also poping your head gasket sounds like you have to much timing. did you have your turbo on when you blew the gasket, or did it just blow. it the turbo was on, try taking out a little more timing on the s200 map.

make sure you running ARP studs and torque them into the block ~10-15 ft/lbs before putting the head on .

 

thanks for the advice. i'll put my adjustable cam gear on again and adjust it so i can set the timig at 12.

as for the arp head studs, i was using them before when the head gasket blew, and i saw the craziest thing. the middle stud looked like it had stretched! under the advice of john, the owner of inlinepro, i went back to stock head bolts for now. he said that with my modest power and boost goals the head studs wont make a difference as long as it's tuned properly.

and yes, i blew the head gasket at the track on the last pass i think. it started overheating a little and the coolant was almost to the top. i removed any air from the cooling system at the track and drove it home.

 

This is a very common problem with y8's converted to obd1. I can only get 11* with the dizzy fully advanced as well. Don't advance your cam gear 1 degree because that will just move your powerband around and 0 degrees with the stock cam should be the best setting. In order to achieve 12* you can advance your entire timing map by 1 degree.

Do you have any pics of your timing maps or do you know what your total timing was when you blew the headgasket?

 

i don't know what my total timing was when i blewthe head gasket, but right now the total timing is at only about 18degrees @ 10psi...he said he set the hondata to like 21 degrees, but that the timing is 3degrees off, so it should be 18. under about 14psi what would a safe timing for 9:1c/r on a pistons/rods sohc?

 

yea my total timing is about 18* as well on my y8 at 10psi.

 

Jeez, these D16 blown headgaskets are starting to get old. We need to get to the bottom of this. I'm replacing my hg in the next two weeks and already have a dyno appt scheduled for April 9. Wish me luck.

 

i hope you get it worked out man. One of us needs to be successful without lifting the head

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SOHC_MShue &raquo;</TD></TR><TR><TD CLASS="quote">i hope you get it worked out man. One of us needs to be successful without lifting the head </TD></TR></TABLE>

for sure.

i have not had any issues on this build yet, but im only pushing 12psi..

 

hey. people think i'm joking when i tell them that i replace the head gasket at about every oil change cause it's leaking. every other time that i replace the head gasket i get the head resurfaced (i alternate with 2 y8 heads). it's rediculous. i was a little scared to push it on the dyno cause i though i had some sort of ignition problem. at the 9-10psi that we tried to tune it at it made 235whp/205wtq consistantly running very conservativly (18degrees total timing). last time at 14psi i did 284whp//250wtq. maybe i'll just take it back and try to get the tuning done.

 

i have consistently had to replace mine every 3 months

 

Mine didn't last a freaking day.

 

haha,

stupid gaskets.

im welding my head to the block.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by platinum00 &raquo;</TD></TR><TR><TD CLASS="quote">haha,

stupid gaskets.

im welding my head to the block.

</TD></TR></TABLE>

I think we're going to have no other option. lol

 

lmao i've thought about that before too. If the motor breaks and you can't get the head off its no big deal because a new one doesn't cost much . Well guys i did a WOT pull today and checked my plugs after turning the timing up and they were PERFECT. very lightish brown with no signs of detonation.

 

good stuff. hope it holds.

 

i still say we need some type of external setup to help hold down the head to the block...

maybe really large clamps LOL

 

i dunno...if 10 arp head bolts torqued to 80ft-lbs doesn't do it, i dont know what will.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sohcmasta &raquo;</TD></TR><TR><TD CLASS="quote">i dunno...if 10 arp head bolts torqued to 80ft-lbs doesn't do it, i dont know what will.</TD></TR></TABLE>

damn... 80ft-lbs?

that would overstretch the studs

 

yea if you are torqueing them to 80 then you shouldn't reuse them a second time. Make sure you get new ones when you need to take the head off.

 

what would you torque them to? like 65-60ft-lbs?

 

torque them into the block about 10-15 ft/lbs before putting the head on.

then 65 ft/lbs in incraments of 20. so 20 / 40 /60 /65.

then 10 heat cycles , retorque

 

thats exactly what i did this last time

 

honeslty guys, i have not heard of a problem yet when following that procedure.

just because i have not heard it does not mean it hasnt happend though..


wonder if the studs are backing themselves out a bit causes less torque on the head, and then once boost gets under, bye bye gasket..